This invention relates to devices for continuously incubating chemical analysis measurement units, and more particularly to an incubator which is employed in a clinical chemical examination system for performing quantitative analysis of a particular component included in a liquid specimen or body fluid such as blood or urine.
In present medical treatment, clinical chemical examination is essential for correct diagnosis and suitable medical care. Examination is carried out according to an enzyme measurement method in which an enzyme is used to measure a stroma; an immunity measurement method in which an antigen antibody reaction is utilized to quantitatively measure the antigen and antibody, and/or a method measuring the activity of non-organic ions in the body fluid.
In the immunity measurement method, the antigen and antibody are marked by some means, to quantitatively trace the antigen and antibody reaction. The marking may be effected with an enzyme, red corpuscle, bacteriophage, fluorescent material, radioactive isotope or special metal compound.
Measurement principles employed in the enzyme measurement method and in the enzyme iummunity measurement method using a marked enzyme are grouped into the spectral measurement method, fluorescent method and the electrode method. In spectral measurement, the variation in the absorbancy of a stroma or product is subjected to colorimetric determination, and in the case when no coloring reaction takes place with the stroma, a suitable coloring reagent which colors with the stroma or product is used. The fluorescent method is used in the case where a product of the enzyme reaction is a fluorescent material, and the sensitivity of this method is generally 100 to 1,000 times that of the spectral measurement method. In the electrode method, the variation of hydrogen ions caused by a hydrolysis reaction is measured, or the amount of oxygen in a liquid specimen changed by an oxygen reduction reaction is measured with an oxygen electrode. The enzyme measurement and the enzyme immunity measurement methods should be suitably selected according to the object to be measured.
In the enzyme measurement method, for instance, separated blood plasma, a dilute solution and an enzyme solution are poured into a cell, and are subjected to enzyme reaction in an incubator after being sufficiently mixed. The incubator is made up of a bath filled with water, and a heating source for maintaining the water bath at a predetermined temperature, for instance 37.degree. C. The cell is incubated in the incubator for five to ten minutes. After incubation, light of a predetermined wavelength range, for instance from the near ultraviolet (190 to 400 nm) to the visible range (400 to 800 nm) is applied to the cell from one side thereof. The light passing through the cell and the solution is subjected to photo-electric conversion in a photo-detector and the stroma is quantitatively analyzed from its absorbancy. In the fluorescent method, a fluorophotometer is used to measure light from the product. In the electrode method, a pair of electrodes are inserted into a test tube, to measure the hydrogen ions or the like which are produced by the hydrolysis reaction.
However, the above-described method in which the cell or the test tube is used is disadvantageous in that a large quantity of liquid specimen is necessary, the operation is rather troublesome, measurement cannot be readily and quickly achieved and a number of liquid specimens cannot be continuously measured. In order to overcome these difficulties, a chemical analysis measurement unit has been proposed in which a measurement element such as a reagent layer is incorporated in a thin plastic frame (or container). One example of a chemical analysis measurement unit which is used in the spectral measurement method is described in the specification of Japanese Utility Model Application No. 41787/1980. The unit comprises a measurement element consisting of a transparent base layer, a reagent layer and a spread layer; a lower slide frame having a colorimetric hole at the center; and an upper slide frame having a liquid specimen dropping hole at the center, the peripheral portions of the two slide frames being welded together with the measurement element set between the two slide frames.
A chemical analysis measurement unit using a measurement element in the form of a dry multi-layer film is called a chemical analysis slide. In the case of the slide, a liquid specimen is dropped through a hole in the upper slide frame. After the liquid specimen has spread, the slide is incubated at 37.degree. C. for six minutes so that a coloring reaction sufficiently takes place. Then, light is applied through the hole of the lower slide frame, so that light reflected from the reagent layer is subjected to colorimetric measurement to perform a quantitative analysis of a particular component.
The chemical analysis measurement unit using the frames can be used not only in the spectral measurement method, but also in the fluorescent method and the electrode method.
A unit for measuring the activity of non-organic ions in a liquid specimen, as disclosed by Japanese Patent Application Laid-Open No. 20499/1980, comprises a pair of solid electrodes; a porous material disposed between the solid electrodes; and a frame which incorporates these measuring elements and has a plurality of fluid insertion holes on one side. The frame further has terminals connected to the solid electrodes; and an electrometer is connected to the terminals. Under this condition, a reference body fluid is dropped through the frame's hole, while a liquid specimen is dropped through the other hole, thus forming a capillary bridge. The potential between the two electrodes is measured during incubation, to obtain the activities of such ions as K.sup.+, Na.sup.+, Ca.sup.+, Cl.sup.- and HCO.sub.3.sup.- in the liquid specimen.
For analytic measurement with high accuracy, the above-described chemical analysis measurement unit should be incubated at a temperature and for a period of time which is suitable for reaction conditions. However, almost all the conventional incubators employ baths. That is, an apparatus for readily and efficiently incubating chemical analysis measurement units having such thin frames has not been proposed in the art.